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Improved understanding and compact descriptions of the pressure drop evolution of Particulate Filters (both for diesel and gasoline powered vehicles) are always in demand for intelligent implementations of exhaust emission system monitoring and control. In the present paper we revisit the loading process of a particulate filter focusing on a parametric description of the deep bed-to-cake transition in the light of recent progress in the understanding of soot deposit structure, growth dynamics and evolution. Combining experimental data, simulation models and information theoretic concepts we provide a closed-form representation of the entire evolution of pressure drop (from the initial clean state up to the evolving linear cake growth regime) parameterized in terms of the physical parameters of the system (filter and particle structure/geometry and flow properties).

The measurement of vehicle particle number emissions and, therefore, regulation, necessitates a rigorous sampling and conditioning technology able to deliver solid emitted particles with minimum particle losses. European legislation follows a solid particle number measurement method with cutoff size at 23 nm proposed by the Particle Measurement Programme (PMP). Accordingly, the raw exhaust is sampled with constant volume, subsequently passes through a volatile particle remover (VPR), and finally is measured with a particle counter. Lowering the 23 nm cutoff size with current VPR technologies introduces measurement uncertainties mainly due to the high particle losses and possible creation of artefacts. This study describes the development and evaluation of a sampling and conditioning particle system, the SCPS, specially designed for sub-23 nm solid particles measurement.

Diesel and gasoline direct injection engines emit nucleation mode particles either under special conditions or as part of their normally emitted size distribution, respectively. Currently, European legislation excludes nucleation mode particles as particle number vehicle emission measurements are limited down to 23 nm. The rationale behind such a cut-off size is based on the avoidance of significant uncertainties inherent in the sampling and measuring of sub-23 nm solid particles. However, the sub-23 nm particles have drawn increased attention since a large fraction of particles emitted by modern vehicles lies in this size range. In this study we investigate the possibility of accurate nucleation mode particles detection by using the Advanced Half Mini Differential Mobility Analyzer (HM-DMA).

Evolving marine diesel emission regulations drive significant reductions of nitrogen oxide (NOx) emissions. There is, therefore, considerable interest to develop and validate Selective Catalytic Reduction (SCR) converters for marine diesel NOx emission control. Substrates in marine applications need to be robust to survive the high sulfur content of marine fuels and must offer cost and pressure drop benefits. In principle, extruded honeycomb substrates of higher cell density offer benefits on system volume and provide increased catalyst area (in direct trade-off with increased pressure drop). However higher cell densities may become more easily plugged by deposition of soot and/or sulfate particulates, on the inlet face of the monolithic converter, as well as on the channel walls and catalyst coating, eventually leading to unacceptable flow restriction or suppression of catalytic function.

This collection is a resource for studying the history of the evolving technologies that have contributed to snowmobiles becoming cleaner and quieter machines. Papers address design for a snowmobile using the EPA test procedure and standard for off-road vehicles, along with more stringent U.S. National Park Best Available Technology (BAT) standards that are likened to those of the California Air Resourced Board (CARB). Innovative technology solutions include: • Standard application for diesel engine designs • Applications to address and test both engine and track noise • Benefits of the Miller cycle and turbocharging The SAE International Clean Snowmobile Challenge (CSC) program is an engineering design competition. The program provides undergraduate and graduate students the opportunity to enhance their engineering design and project management skills by reengineering a snowmobile to reduce emissions and noise.

This collection is a resource for studying the history of the evolving technologies that have contributed to snowmobiles becoming cleaner and quieter machines. Papers address design for a snowmobile using the EPA test procedure and standard for off-road vehicles. Innovative technology solutions include: • Engine Design: improving the two-stroke, gas direct injection (GDI) engine • Applications of new muffler designs and a catalytic converter • Solving flex-fuel design and engine power problems The SAE International Clean Snowmobile Challenge (CSC) program is an engineering design competition. The program provides undergraduate and graduate students the opportunity to enhance their engineering design and project management skills by reengineering a snowmobile to reduce emissions and noise. The competition includes internal combustion engine categories that address both gasoline and diesel, as well as the zero emissions category in which range and draw bar performance are measured.

This collection is a resource for studying the history of the evolving technologies that have contributed to snowmobiles becoming cleaner and quieter machines. Papers address design for a snowmobile using E10 gasoline (10% ethanol mixed with pump gasoline). Performance technologies that are presented include: • Engine Design: application of the four-stroke engine • Applications to address both engine and track noise • Exhaust After-treatment to reduce emissions The SAE International Clean Snowmobile Challenge (CSC) program is an engineering design competition. The program provides undergraduate and graduate students the opportunity to enhance their engineering design and project management skills by reengineering a snowmobile to reduce emissions and noise. The competition includes internal combustion engine categories that address both gasoline and diesel, as well as the zero emissions category in which range and draw bar performance are measured.

Recognition of Dimethyl Ether (DME) as an alternative fuel has been growing recently due to its fast evaporation and ignition in application of compression-ignition engine. Most importantly, combustion of DME produces almost no particulate matter (PM). The current study provides a further understanding of the combustion process in DME reacting spray via experiment done in a constant volume combustion chamber. Formaldehyde (CH2O), an important intermediate species in hydrocarbon combustion, has received much attention in research due to its unique contribution in chemical pathway that leads to the combustion and emission of fuels. Studies in other literature considered CH2O as a marker for UHC species since it is formed prior to diffusion flame. In this study, the formation of CH2O was highlighted both temporally and spatially through planar laser induced fluorescence (PLIF) imaging at wavelength of 355-nm of an Nd:YAG laser at various time after start of injection (ASOI).

Catalysts that have been extensively investigated for direct soot oxidation in Catalyzed Diesel Particulate Filters (CDPFs) are very often based on mixed oxides of ceria with zirconia, materials known to assist soot oxidation by providing oxygen to the soot through an oxidation-reduction catalytic cycle. Besides the catalyst composition that significantly affects soot oxidation, other parameters such as morphological characteristics of the catalyst largely determined by the synthesis technique followed, as well as the reagents used in the synthesis may also contribute to the activity of the catalysts. In the present work, two ceria-zirconia catalyst samples with different zirconia content were subjected to different milling protocols with the aim to shift the catalyst particle size distribution to lower values. The produced catalysts were then evaluated with respect to their soot oxidation activity following established protocols from previous works.

Dimethyl ether (DME) appears to be an attractive alternative to common fossil fuels in compression ignition engines due to its smokeless combustion and fast mixture formation. However, in order to fully understand the complex combustion process of DME, there is still a remaining need to develop a comprehensive chemical kinetic mechanism that includes both soot and NOx chemistry. In this study, a detailed DME mechanism with 305 species is developed from the basic DME mechanism of Curran et al. (2000) with addition of soot and NOx chemistry from Howard's mechanism et al. (1999), and GRI 3.0 mechanism, respectively. Soot chemistry in Howard mechanism consisting hydrogen abstraction acetylene addition (HACA) and growth of small polycyclic aromatic hydrocarbons (PAH), assesses over a wide range of temperature and is able to predict good to fair the formation of PAH up to coronene.

Two modern light-duty passenger vehicles were selected for chassis dynamometer testing to evaluate differences in performance end efficiency resulting from CNG and gasoline combustion in a vehicle-based context. The vehicles were chosen to be as similar as possible apart from fuel type, sharing similar test weights and identical driveline configurations. Both vehicles were tested over several chassis dynamometer driving cycles, where it was found that the CNG vehicle exhibited 3-9% lower fuel economy than the gasoline-fueled subject. Performance tests were also conducted, where the CNG vehicle's lower tractive effort capability and longer acceleration times were consistent with the lower rated torque and power of its engine as compared to the gasoline model. The vehicles were also tested using quasi-steady-state chassis dynamometer techniques, wherein a series of engine operating points were studied.

High hydrocarbon (HC) emission during a cold start still remains one of the major emission control challenges for spark ignition (SI) engines in spite of about three decades of research in this area. This paper proposes a cold start HC emission control strategy based on a reduced order modeling technique. A novel singular perturbation approximation (SPA) technique, based on the balanced realization principle, is developed for a nonlinear experimentally validated cold start emission model. The SPA reduced model is then utilized in the design of a model-based sliding mode controller (SMC). The controller targets to reduce cumulative tailpipe HC emission using a combination of fuel injection, spark timing, and air throttle / idle speed controls. The results from the designed multi-input multi-output (MIMO) reduced order SMC are compared with those from a full order SMC. The results show the reduced SMC outperforms the full order SMC by reducing both engine-out and tailpipe HC emission.

Vehicle operation during cold-start powertrain conditions can have a significant impact on drivability, fuel economy and tailpipe emissions in modern passenger vehicles. As efforts continue to maximize fuel economy in passenger vehicles, considerable engineering resources are being spent in order to reduce the consumption penalties incurred shortly after engine start and during powertrain warmup while maintaining suitably low levels of tailpipe emissions. Engine downsizing, advanced transmissions and hybrid-electric architecture can each have an appreciable effect on cold-start strategy and its impact on fuel economy. This work seeks to explore the cold-start strategy of several passenger vehicles with different powertrain architectures and to understand the resulting fuel economy impact relative to warm powertrain operation. To this end, four vehicles were chosen with different powertrain architectures.

This study evaluates iso-butanol as a pathway to introduce higher levels of alternative fuels for recreational marine engine applications compared to ethanol. Butanol, a 4-carbon alcohol, has an energy density closer to gasoline than ethanol. Isobutanol at 16 vol% blend level in gasoline (iB16) exhibits energy content as well as oxygen content identical to E10. Tests with these two blends, as well as indolene as a reference fuel, were conducted on a Mercury 90 HP, 4-stroke outboard engine featuring computer controlled sequential multi-port Electronic Fuel Injection (EFI). The test matrix included full load curves as well as the 5-mode steady-state marine engine test cycle. Analysis of the full load tests suggests that equal full load performance is achieved across the engine speed band regardless of fuel at a 15-20°C increase in exhaust gas temperatures for the alcohol blends compared to indolene.

Aluminum based brake rotors have been a priority research topic in the DOE 1999 Aluminum Industry Roadmap for the Automobile Market. After fourteen years, no satisfactory technology has been developed to solve the problem of aluminum's low working temperatures except the steel clad aluminum (SCA) brake technology. This technology research started at Michigan Technological University (MTU) in 2001 and has matured recently for commercial productions. The SCA brake rotor has a solid body and replaces the traditional convective cooling of a vented rotor with conductive cooling to a connected aluminum wheel. Much lower temperatures result with the aluminum wheel acting as a great heat sink/radiator. The steel cladding further increases the capability of the SCA rotor to withstand higher surface temperatures. During the road tests of SCA rotors on three cars, significant gas mileage improvement was found; primarily attributed to the unique capability of the SCA rotor on pad drag reduction.

The EU emission standards for new rail Diesel engines are becoming even more stringent. EGR and SCR technologies can both be used to reduce NOx emissions; however, the use of EGR is usually accompanied by an increase in PM emissions and may require a DPF. On the other hand, the use of SCR requires on-board storage of urea. Thus, it is necessary to study these trade-offs in order to understand how these technologies can best be used in rail applications to meet new emission standards. The present study assesses the application of these technologies in Diesel railcars on a quantitative basis using one and three dimensional numerical simulation tools. In particular, the study considers a 560 kW railcar engine with the use of either EGR or SCR based solutions for NOx reduction. The NOx and PM emissions performances are evaluated over the C1 homologation cycle.

In this paper, a methodology is presented to study the influence of thermal aging on catalytic DPF performance using small scale coated filter samples and side-stream reactor technology. Different mixed oxide catalytic coating families are examined under realistic engine exhaust conditions and under fresh and thermally aged state. This methodology involves the determination of filter physical (flow resistance under clean and soot loaded conditions and filtration efficiency) and chemical properties (reactivity of catalytic coating towards direct soot oxidation). Thermal aging led to sintering of catalytic nanoparticles and to changes in the structure of the catalytic layer affecting negatively the filter wall permeability, the clean filtration efficiency and the pressure drop behavior during soot loading. It also affected negatively the catalytic soot oxidation activity of the catalyzed samples.

Numerical modeling of aftertreatment systems has been proven to reduce development time as well as to facilitate understanding of the internal physical and chemical processes occurring during different operating conditions. Such a numerical model for a catalyzed diesel particulate filter (CPF) was developed in this research work which has been improved from an existing numerical model briefly described in reference. The focus of this CPF model was to predict the effect of the catalyst on the gaseous species concentrations and to develop particulate matter (PM) filtration and oxidation models for the PM cake layer and substrate wall so as to develop an overall model that accurately predicts the pressure drop and PM oxidized during passive oxidation and active regeneration. Descriptions of the governing equations and corresponding numerical methods used with relevant boundary conditions are presented.

This paper describes the durability of the filtration layer integrated into Diesel Particulate Filters (DPFs) that we have developed to ensure low pressure loss and high filtration efficiency performances which also meet emission regulations. DPF samples were evaluated in regards to their performance deterioration which is brought about by ash loading and uncontrolled regeneration cycles, respectively. Ash was synthesized by using a diesel fuel/lubrication oil mixture and was trapped up to a level which corresponded to a 240,000km run, into the DPFs both with and without the filtration layer. Afterwards, aged-DPFs were measured with respect to their permeability, pressure loss, filtration efficiency, as well as soot oxidation speed using suitable analytical methods. Consequently, it has been confirmed that there was no noteworthy deterioration of the performances in the DPF with the filtration layer.

Despite the great effort devoted to the modeling of the operation of catalytic DPFs, even today very simple expressions are used for the soot oxidation rate. In the relevant to DPF operation case of a gas phase rich in oxygen, the structure of the soot-catalyst geometry and its evolution during oxidation determines the reaction rate. An extensive set of controlled experiments (isothermal or with linear temperature increase) using fuel borne catalysts and catalytic coatings has been performed in order to obtain corresponding soot oxidation rate-conversion curves. The shape of the resulting curves cannot be described by the typical theories for solid phase reactions posing the need for microstructural models for the micromechanics of soot catalyst interactions.